Ribosomes and mitochondria are both found inside cells, but in different specific places and with different jobs.

Where to find ribosomes

Ribosomes are the tiny protein-making machines of the cell. You can find them:

  • Floating freely in the cytoplasm, making proteins that stay inside the cell.
  • Attached to the rough endoplasmic reticulum (RER), making proteins that are usually sent out of the cell or to membranes.
  • Inside mitochondria (and in plant cells, also inside chloroplasts), where they make a few special internal proteins.

So if you “zoom in” on a typical animal or plant cell, ribosomes are scattered in the cytoplasm, studding the rough ER, and also present inside mitochondria.

Where to find mitochondria

Mitochondria are the powerhouse organelles that make most of the cell’s ATP energy. They are:

  • Found in the cytoplasm of almost all eukaryotic cells (animal, plant, fungi, protists).
  • Especially numerous in cells that need a lot of energy, like muscle cells, nerve cells, and heart cells.
  • Enclosed by two membranes, with an inner folded membrane and a fluid-filled matrix inside.

In short:

  • Ribosomes = all over the cell (cytoplasm, rough ER, inside mitochondria/chloroplasts).
  • Mitochondria = energy factories floating in the cytoplasm of eukaryotic cells, often in large numbers where energy demand is high.

Information gathered from public forums or data available on the internet and portrayed here.